a. Field of the Invention
The instant invention relates to an ultrasonic endovascular clearing device. In particular, the instant invention relates to an ultrasonic endovascular clearing device for clearing plaque, thrombosis and other blockages and/or restrictions in bodily lumens. Such lumens are typically natural lumens but may also include implanted lumens such as grafts and stents.
b. Background Art
It is known to employ various apparatus to clear fouled or blocked bodily lumens (e.g., blood vessels). Historically, conventional devices were incapable of the semi-invasive time efficient clearing of substantial lengths of lumen deposits in a reasonable time, if at all. For example, existing catheter-based devices perform their cleaning action only at their local tip position in the lumen. Such devices also have the propensity to cause lumen damage due to high balloon pressures (if they utilize balloons) and/or outright tip mechanical punctures of the lumen walls even if they do not utilize balloons. Restenosis is also a problem when such tissue insult is delivered.
A more recent approach in the art for endovascular clearing of blockages and other deposits involves an ultrasonic lateral-wave wire-based device. Such a device, in operation, involves the use of a small diameter titanium or titanium-alloy wire that is acoustically excited to transversely oscillate with multiple nodes and anti-nodes along its length. The oscillating wire is fed through fouled or blocked bodily lumens, with or without an assisting dissolution drug, to clean the lumen along its entire length simultaneously. Omnisonics of Wilmington, Mass. makes such a transverse oscillation wire system.
There are at least two issues with these wire-cleaning devices. The first and most clinically relevant is that it tends to be highly damped when routed around tight corners. This damping bleeds off most of the cleaning energy rendering the rest of the wire vibrationally ineffective. The lateral vibration mode is particularly subject to such damping.
The second issue is that such a device is subject to a certain amount of fatigue and that the large-displacement lateral or radial motions induce very high oscillatory wires stresses. Accordingly, such wires must be disposable (i.e., single or limited use). Although disposable wires are desirable for sanitary reasons, the fatigue described above increases the risk of a wire break during even a single use.
There is therefore a need to minimize or eliminate one or more of the problems set forth above.